It has been a common practice to use particulate toner as the developer for an electrophotographic image forming apparatus such as a copying machine or printer. As the toner in the main assembly of an image forming apparatus is consumed, the main assembly of the image forming apparatus is replenished with toner with the use of a toner supply container.
Generally, toner is in the form of extremely fine powder. Thus, one of the known methods for preventing toner from scattering during an operation for replenishing the main assembly of an image forming apparatus is to place a toner supply container in the main assembly of the image forming apparatus, and discharge toner little by little through the tiny opening of the toner supply container.
The toner replenishing apparatus, in accordance with the prior art, usable with the above described toner replenishing methods is structured so that the cap of the toner supply container can be removed by some kind of means, and some kind of driving force is transmitted to the toner supply container to drive the toner conveying member on the toner supply container side; or the toner supply container itself, which is given such a configuration that enables it to convey toner, is rotated to discharge the toner therefrom.
Also in the case of the toner replenishing apparatus in accordance with the prior art, by the time a user is forced to replace the replenishment toner container, the image forming apparatus will have been completely depleted of toner, by consumption.
Thus, Japanese Laid-open Patent Application 11-038755 discloses a method, shown in FIG. 35, for detecting the amount of toner remaining in a toner container.
This toner container 46k employs such a structural arrangement that as a spiral coil 46b disposed in the toner container 46k is rotated, the toner is conveyed and discharged.
A light sensor 900 solidly disposed on the main assembly side of the image forming apparatus is structured so that it projects a beam of light toward a light beam guiding member 901 of the replenishment toner container, and catches the beam of light reflected back by the light beam guiding member 901.
Thus, when there is toner in the replenishment toner container, the beam of light is blocked by the body of toner. Therefore, the beam of light does not return to the light sensor 901, indicating the presence of toner. On the other hand, if the beam of light returns to the light sensor 901, it is determined that there is no toner in the replenishment toner container.
Further, Japanese Laid-open Patent Application 11-038755 proposes to apply the above described toner remainder amount detecting method to a toner container, such as the one shown in FIG. 36, which is structured so that as the container itself is rotated, the toner in the container is conveyed and discharged.
More specifically, this replenishment toner container 46k is provided with spiral grooves, which are cut in the internal surface of the container 46k, being extended from the rear end of the container 46k, in terms of the toner conveyance direction, to an opening 46a of the container 46k. Thus, as the replenishment toner container is rotated, the toner therein is discharged through the opening 46a, and falls into the hopper portion of the image forming apparatus. After falling into the hopper portion, the toner is conveyed toward the developing device by a screw 49k disposed in the hopper portion.
The structural arrangement disclosed in Japanese Laid-open Patent Application 11-038755, however, suffers from the following technical problems.
That is, the structural arrangement is such that the toner sensor 900 for detecting the amount of the toner remaining in the replenishment toner container is disposed on the main assembly side of the image forming apparatus, making it necessary to employ a toner sensor with a long service life, as the toner sensor 900. Further, the information regarding the amount of the toner remainder in the replenishment toner container can be obtained only in the binary fashion; in other words, only the information regarding whether or not the amount of the toner remaining in the replenishment toner container is more than a predetermined amount can be detected.
Thus, the employment of the above-described method for detecting the amount of the toner remainder was problematic in that it increased the cost of the image forming apparatus, and also, that it made the image forming apparatus complicated in structure. Further, in the case of the above-described method, a user was not informed of toner depletion until the replenishment toner container was completely depleted of the toner therein. Therefore, for a user who happened to have no replenishment toner container at hand, nothing was more inconvenient than being informed of the fact that the replenishment toner container in the image forming apparatus was completely depleted of the toner.